Compounded hydrocarbon oil



s "'VPA'TENT orrics COMPOUNDED HYDROCARBON OIL Joseph F. Nelson,Elizabeth, and Louis A. Mike ska, Westfield, N. J., assignors toStandard Oil Development Company, a corporation of Dclaumrao STATE ware1 No Drawing. Application August 18, 1942,

., Serial No. 455,244

7 Claims. (Cl. 252-3211) This invention relates to lubricating oils andother products and to a new type of additive for improving theproperties of such products as well as other organic materials. Moreparticularly,

ing an organic substituent therein. The acids of phosphorus from whichthese compounds are derived include especially the acids of trivalentand pentavalent phosphorus, particularly phosphothe invention relates tothe compounding of lurous acid, HaPOa, hypophosphorous acid, HaPOa,bricating oils suitable for use as crankcase lubrind Orthophespherieacid, 3P 4- These acids cants for internal combustion engines. includeparticularly those in which an oil-solu- Because in recent years therequirements for bilizing organic r p i Substituted r e lubricating oilsfor gasoline and Diesel engines more of the hyd ogen atoms of the acid.In the a have steadily been made more stringent, it has in m t llic sals erived from these acids one or been proposed to add variousingredients to these more of the valence bonds of a given metallic oilsto improve their behavior in such service. atom may be Joined to asingle acid radical. Al- One property of these ingredients is to'impartthough sulfur is a preferred component of the detergency to the oils,thus bringing about greater salts used according to the presentinvention, engine cleanliness and avoiding ring sticking, the elementsselenium and tellurium maybesu'bcarbon formation, and varnishdeposition. Cerstituted for such sulfur to form compounds which tain ofthese ingredients also afford oxidation reare similarly effective. Theorganic substituent sistance properties to oils thereby tending toinwhich is a necessary part of the structure'of the hibit sludgeformation and the development of preferred compounds should be one whichimcorrosi-ve ingredients in such oils. Corrosion prparts adequate oilsolubility to the compounds, venting agents'are particularly requiredwhen the 11 they are to be incorporated in mineral lubrioil is to comeinto contact at high temperatures cating oils. with the newer type ofalloys of silver and cad- Although salts derived from all of the sulfurmiuzm and of copper and lead, which ar now containing acidsof phosphorusare useful in ac- 'widely used as bearing materials. cordance with thepresent invention, it has been Various metal containing organiccompounds, found that an exceptionally valuable class of particularlythe metallic salts of fatty acids, have compounds includes thepolyvalent metal salts of been found to be quite effective asdetergents, but sulfur containing substituted acids of trivalent thesematerials have the very great disadvantage phosphorus having an organicsubstituent thereof being corrosive to metal parts, particularly to in.These include particularly the salts of thiothe surfaces of alloybearings. Also, certain ph sph s a id s p fe rede up f mmetallic saltsof inorganic acids having substitpounds may be defined more particularlyby the uent oil-solubilizing organic groups have been general formulafound effective as detergents. Typical examples of these are cadmium,tin, and cobalt mahogany URXMAHY) sulfonates. Such additives are notalways satis- Where X, and Z represent y lfur. factory and often tend toincrease the corrosive- Selenium, and tenuriumat One tom f ness of oilsin which they are used. c sulfur. e e or tellurium being present. H Itis an object of the present invention to pro- 6. P p e t ydrogen andPhosphorus, vide a new class of additives for lubricating oils 40 ptively, R represents an orga ic ro p. a, which are not only notcorrosive when blended d d r pres nt sma l whole num ers. th total withsuch oils but also have the property of in- Of and 6 being e b beingZero e. hibiting the normal corrosive tendency of the oils and Mrepresents p yv n m l, Pr f toward coppeplead and imilar bearingg Thesean alkaline earth metal. Where more than one new additives also improveengine cleanliness and Organic group R occurs in the Compound. Snehreduce ring sticking, piston skirt varnish and groups y be al e 0 d fiThe Organic sludge tendencies of oils used in automotive enroups may ealkyl, ryl, alkaryl, aralkyl, or gines. They are also effectiveantioxidants for h t r y lic r ps, and th y may include subother typesof organic compounds, as will be more stituent groupsor atoms, such ashalogen atoms, fully set forth below. y yl p m p p amino groups, The newclass of additives for lubricating oils carbo yl roups and organic gr pscont n and other products which have been found to metals, as well asaryl and alkyl substituted depossess the valuable properties enumeratedabove ,rivatives of such groups. comprises the polyvalent metal salts ofsulfur The group R n e p un defined above containing substituted acidsof phosphorus hav- 65 ho ld b an oil-solubilizing group h n th mpound isto be dissolved in a mineral oil. Although alkyl radicals of 5 to carbonatoms will often-serve adequately as oil-solubilizing groups, moresatisfactory products can be obtained if the alkyl group has from 12 to20 or more carbon atoms, particularly if the additives are to be used inhighly paramnic base oils, since the latter generally do not possess asgood solvent power as naphthenic base oils. Also, very desirableproducts can be prepared with alkylated phenols, such as isooctylphenol, tert.-amyl phenol or octadecyl phenol, as starting materials.

Typical acids from which these metal salts are derived are representedby the following formulas:

P--O'R R Di-ester of monothiophosphorous acid /SH PSR SR Monothio-esterof trithiophosphorous acid SR Monothio-ester oi monothiophosphorous acidIn the above'formulas R and R' may be any organic group as defined inthe preceding paragraph.

A subclass of compounds which are particularly suitable for the purposesof the invention and readily obtainable are the alkaline earth salts ofacids of the formula HSP(OR) z where R is an oilsolubilizing organicgroup.

Typical examples of compounds which are particularly useful inlubricating oils are the followin O-GaHn P O-CaHu Barium dioctylmonothiophosphlte 0-Cs Hu Calcium diamyl monothiophosphite -CiaHi1Magnesium dioctadocyl monothiophosphite Other typical examples ofcompounds illustrating the new group of lubricating oil additives asdefined by the present invention include barium dicetyl dithiophosphite,zinc dicyclohexyl monothiophosphite, aluminum di(tert.-aTmyl phenyl)monothiophosphite, tin monolauryl dithiophosphite, cobalt naphthenylmonothiophosphite, nickel dioleyl dithiophosphite, calcium dioctyltrithiophosphite, magnesium diiisooctyl phenyl) monothiophosphite,barium di(isooctyl phenyl) monothiophosphite, calcium di(isooctylphenyl) monothiophosphite, monothiophosphite, monothiophosphite,monothiophosphite, monothiophosphite.

Although preference has been expressed for the metal salts ofthiophosphorous acids, the invention is not limited to such compounds,but includes also polyvalent metal salts, especially the alkaline earthmetal salts, of other sulfur containing acids of phosphorus, or acids ofphosphorus containing selenium or'tellurium in place of sulfur,particularly the sulfur containing phosphoric acids. Examples ofcompounds of this type which are effective as lubricating oil addibariumoctadecyl phenyl magnesium eicosyl phenyl and zinc tetracosyl phenyltives and which do not exhibit the corrosive ef- Eects found in othermetal containing organic compounds are barium dioctyl dithiophosphate,calcium dioctyl dithiophosphate, magnesium monolauryl monothiophosphate,zinc dioctadecyl trithiophosphate, tin dicetyl dithiophosphate, nickelcyclohexyl monothiophosphate, tin di(tert.- butyl phenyl)trithiophosphate, aluminum dicresyl dithiophosphate, calciumdi(tert.-amyl phenyl) dithiophosphate, barium di(isooctyl phenyl)dithiophosphate, magnesium di(dodecyl phenyl) dithiophosphate, zincdi(hexadecyl phenyl) dithiophosphate, calcium di(eicosylphenyl)dithiophosphate, barium di(tetracosyl phenyl) dithiophosphate, calciumdilauryl dithiophosphate, barium dioleyl dithiophosphate, magnesiumdicetyl dithiophosphate, and zinc dioctadecyl dithiophosphate.

calcium hexadecyl phenyl than approximately 0.02%, preferably greaterthan approximately 0.05%, and the amount may be as high as 2% or even orhigher, if desired. The exact amount to be used depends to a certainextent on the particular compounds used, the character of the mineraloilbaseand the operating conditions of the engine in which the lubricant isto be employed.

The following examples illustrate methods of preparing the preferredcompounds of the present invention and typical tests which have beenapplied to demonstrate their usefulness in lubricating oils. Theseexamples are given asillustrations only and are not to be considered aslimiting the scope of the invention in any way.

EXAMPLE 1 Preparation of barium dioctyl dithiophosphate Dioctyldithiophosphoric acid was first prepared by heating a mixture of 520parts by weight of 2-ethyl hexanol and 222 parts by weight of powderedphosphorus pentasulflde to about 80 C. with agitation for 34 hours,agitating for a further period of about 16 hours at 40-60 C. with a slowstream of air passing through the flask, and filtering to removeunreacted phosphorus pentasulfide. The crude product was neutralizedwith alcoholic sodium hydroxide and the alcohol and water of reactionwere stripped 'ofi under vacuum leaving a straw colored clear viscousoil. 75 partsby weight of this sodium salt of dioctyl dithiophosphoricacid were dissolved in 120 parts parts by weight of sodium hydroxide inabsolute methyl alcohol. To this solution was added 18 parts by weightof calcium chloridein methyl alcohol. The resulting product was filteredand the alcohol evaporated ofl. Naphtha was added and the undissolvedmaterial filtered off. The

by weight of absolute alcohol, and 36 parts by weight of barium bromide(BaBrz.2HzO) were added along with about 80 parts by weight ofadditional alcohol. It was found 'that the barium bromide was not verysoluble in the alcohol, but by agitating the mixture substantially allof the barium bromide was made to react. The alcoholic solution wasevaporated and the residue taken up with ethyl ether. The ether solutionwas filtered and then evaporated, leaving 63 parts by weight of strawcolored semi-fluid material which was found to consist chiefly of thebarium salt of dioctyl dithiophosphoric acid.

0 EXAMPLE 2 Preparation of barium dioctyl mon thz'ophosphite The sodiumsalt of dioctyl monothiophosphorous acid was first prepared by heating amixture of 520 parts by weight of octyl alcohol (2-ethyl hexanol) and158 parts by weight of phosphorus trisulfide to 80-90 C. until no moreH28 was given off, diluting the product with ether, neutralizing withalcoholic sodium hydroxide and stripping off the solvent under vacuum.113 parts by weight of this sodium salt were dissolved in methyl alcoholand added to 62 parts by weight of barium bromide (BaBr'2.2I-I2O) inabout 80 parts by weight of methyl alcohol. The mixture was agitated forone hour after which naphtha was added and the mixture washed with waterto remove NaBr, excess BaBrz and most of the alcohol. The naphtha layerwas evaporated, leaving a clear dark colored oil, found to beprincipally barium dioctyl mono-'- thiophosphite.

' EXAMPLE 3 Preparation of wlcium dioctyl monothiophosphite 83 parts byweight of dioctyl monothiophosphorous acid (CaHnO) rP-SH were added'to10 naphtha was then evaporated from thesolution, leaving a somewhatfluid liquid which was readily soluble in lubricating oil. This productwas found to be mainly calcium dioctyl monothiophosphite.

EXAMPLE 4 Preparation of calcium diamg/l monothiophosphz'te 352 parts byweight of amyl alcohol were added to 158 parts by weight of phosphorustrisulfide and parts of calcium carbonate in a reaction vessel providedwith stirrer and reflux condenser. The mixture was stirred for about 16hours with-' out external heating. During this time the temperature roseto about 50 C. An additional quantity of amyl alcohol (176 parts) wasadded, then the temperature was gradually raised to 100 C. and themixture was allowed to stand on the steam bath overnight. The productwas then filtered and the filtrate heated to 100 C. under 5 mm. vacuumto remove unreacted alcohol. The resulting calcium diamylmonothiophosphite was a clear but rather dark colored fluid oil.

EXAMPLE 5 Preparation of calcium dioctyl dithiophosphate of sodiumcarbonate until no more CO2 was evolved. After filtering, the filtratewas diluted with about 400 parts by weight of absolute ethyl alcohol and360 parts by weight of calcium nitrate in about 800 parts by weight ofethyl alcohol. The resulting precipitated sodium nitrate was filteredofi, the ethyl alcohol removed under vacuum and the residue diluted withabout 1100 parts by weight of petroleum ether and again filtered toremove unreacted calcium nitrate and additional sodium nitrate. Thefiltrate was shaken overnight with mercury to remove free sulfur and themercury sulfide filtered oif. The naphtha was stripped ofi and theresidue was heated to -140 C. for about one-half hour at 3-4 mm.pressure to remove unreacted octyl alcohol. The product consisted ofcalicum dioctyl dithiophosphate.

EXAMPLE 6 Preparation of zinc di(is0octyl phenyl) monothz'Ophosphite 412parts of isooctyl phenol are added to 760 parts of a refined parafllniclubricating oil having a Saybolt viscosity of 52'seconds at 210 F. andthe mixture is heated to 100 0. While the mixture is stirred, 87 partsof phosphorus trisulfide (P487) are added slowly. The temperature isthen raised to -160 C. slowly and 41 parts of zinc oxide are added.After an additional hour of heating and stirring at C., the product isfiltered, yielding a 40% concentrate of zinc di(iso;:ltyl phenyl)monothiophosphite in mineral o Exsmrm '7 magnesium dioctadecylmonothiophosphite 1080 parts of commercial stearyl alcohol are added to1850 parts ing oil of S. A. E. 20 grade and the mixture is heated to 100C. To the mixture there are added slowly with stirring 174 parts ofphosphorus trisulfide (Pisa), and the temperature is gradually raised to160 C. After all of the phosphorus sulfide has reacted, the temperatureis held at 160 C. while 40 parts of magnesium oxide are aded. Stirringis continued for an additional 4 hours at 160 C. and the product isfiltered, yielding a 40% concentrate of magnesium dioctadecylmonothiophosphite in mineral lubricating oil.

Preparation of Bearing corrosion tests Samples of a base oil consistingof a conventionally. refined Coastal naphthenic base mineral lubricatingoil of'55 Saybolt seconds viscosity at 210 F., as well as samples ofthis oil blended with various additives of the present invention,prepared as described in the preceding examples, were subjected to thestandard Underwood bearing corrosion test, which was conducted asfollows:

The polished bearings of the- Underwood machine were thoroughly abradedwith emery cloth to expose a fresh metal surface so that corrosion wouldproceed uniformly, and then accurately weighed. The apparatus was filledwith 1500 cc. of the lubricant under test and the pump and heaterstarted. The oil pressure was regulated to 10 pounds per square inch bymeans of by-pass valves and maintained at this pressure throughout thetest. As soon as the oil attained the desired test temperature theheater and pump were turned off just long enough to put the alreadyprepard and weighed bearings in place. Two copper-lead and twocadmium-silver hearing halves were used simultaneously in each test. Atthe end of the test period the hearings were of a refined minerallubricatthat the metal thiophosphate and thiophosphite salts of thepresent invention do not increase the corrosiveness of the base oiltoward alloy metal bearings and in practically all instances serve toinhibit the slight corrosiveness oi. the base oil.

Exams: 9

- In the following tests the base oil was the same as that used inExample 8. This was blended with calcium 'dioctyl monothiophosphite andwith calcium dioctyl dithiophosphate, and samples of these blends, aswell as a sample of the unblended base oil, were tested in a. singlecylinder Caterpillar Diesel engine equipped with Babbitt bearings andoperated at 16.7 B. H. P. output, 850 R. P. M., 140 F. oil temperatureand 70 F. atmospheric temperature. After each run the engine parts wereinspected and given demerit ratings based on their condition. Theindividual ratings were weighted according to their relative importanceand an overall demerit rating calculated from them. It should be notedthat the lower the demerit rating, the better the engine condition and,hence, the better the periormance of the oil in the engine- The resultsof these engine tests are shown in Table 11.

Table II.

Engine demerits Oil blend Hours Over- Ring Piston Oil 8.1 zone skirtsfilter Base 011 1 60 1.01 1.25 1.0 1 110 1. l. 86 l. 5 2 a 242 l. 96 2.58 2. 0 4

Base oi1+1.0% calcium dioctyl monothiophosphite 1 60 0. 52 0. 37 0. 250. 00 112 0. 71 0. 63 0. 5 0.12 250 1 09 1.48 1. 3 0.50

Base oil+l.0% calcium dioctyl dithiophosphate 60 0. 95 l. 02 0. 12 0. 75

removed, cleaned with naphtha, dried and Table I Bearing weight lossegrams/ Hours sq. cm. area Oil blend m o Base oil Base oil+0.5% nickeloleate... Base oil+0.2% barium dioctyl dithioph osphatc Base oil+0.5%barium dioctyl monothiophosphite Base oil+0.5% calcium dioctylmonothiophosphite Ewe oil Base oil+l .0% calcium dioctylmonothiophosphite Base oil Base oil+0.5% nickel oleate Base o il+l.0%calcium dioctyl dithiophosphate 1 Indicates that bearings gained inweight.

It will be seen from the results of these tests (Id-Ag l 6()hourdemerits ratings were calculated by plotting and 250 hour data andinterpolating. 1

It can be seen frOm the above results that, although the calcium dioctyldithiophosphate showed certain positive improvements over the unblendedoil tested, the blend containing calcium dioctyl monothiophosphite'showed a very distinct superiority over the thiophosphate blend. After112 hours of operation with the thiophosphite blend the engine conditionwas found to be much better than after only 60 hours with thethiophosphate blend. Also, after 250 hours with the thiophosphite blendthe cleanliness'of engine parts was much better than with the base oilalone after only 110 hours of operation.

EXAMPLE 10 High temperature Caterpillar Diesel engine tests In thisseries of tests the same base oil was used as in Example 9, the testsbeing carried out in a high temperature single cylinder CaterpillarDiesel engine fitted with copper-lead bearings and operated at 16.7 B.H. P. output, 850 R. P. M., 195 F. oil temperatureQand F. atmospherictemperature. The engine parts were inspected and given ratings as inExample 9. The results are shown in Table III, which includes also thecopper-lead bearing weight losses.

residuals, particularly Table III Engine demerits Cu-Pb bearing Oilblend Hours weight Over- Ring Piston Oil loss all zone skirts I filtergrams Base oil 60 1. 48 2. 64 1. 0. 75 0.037 Base oil+l.0%

calcium dioctyl dithiophosphate. 60 0. 88 1. 09 0. 0 l. 0. 000

distillates derived from parafiinic, naphthenic,

aspholtic or mixed base crudes, or, if desired, various blended oilsmaybe employed as well as those from which asphaltic constituents havebeen carefully removed. The oils may be refined by conventional methodsusing acid, alkali and/or clay or other agents such as aluminumchloride, or they may be extracted oils produced, for example, bysolvent extraction with solventsof the type of phenol, sulfur dioxide,furfural, dichloro ethyl ether, propane, nitrobenzene, crotonaldehyde,etc. Hydrogenated oils or white oils may be employed as well assynthetic oils prepared, for example, by the polymerization of olefinsor by the reaction of oxides of carbon with hydrogen or by thehydrogenation of coal or its products. In certain instances crackingcoil tar fractions and coal tar or shale oil distillates may also beused. Also, for special applications, animal, vegetable or fish oils ortheir hydrogenated or voltolized products may be employed, either aloneor in admixture with mineral oils.

.For the best results the base stock chosen should normally be that oilwhich without the new additivesv present gives the optimum performancein the. service contemplated. However, since one advantage of theadditives is that their use also makes feasible the employment of lesssatisfactory mineral oilsor other oils, no strict rule can be laid downfor the choice of the base stock. Certain essentials must of course beobserved. The oil must possess the viscosity and volatilitycharacteristics known to be required for the service contemplated. Theoil must be a satisfactory solvent for the additive, although in somecases auxiliary solvent agents may be used. The lubricating oils,however the mayhave been produced, may vary considerably in viscosityand other properties depending upon the particular use for which theyare desired, but they usually range from about 40 to 150 seconds Sayboltviscosity at 210 F. For the lubrication of certain low and medium speedDiesel engines the general practice has often been to use a lubricatingoil base stock prepared from naphthenic or aromatic crudes and having aSaybolt viscosity at 210 F. of 45 to 90 seconds and a. viscosity indexof However, in certain types of Diesel service, particularly with highspeed Diesel engines, and in gasoline engine service, oils of higherviscosit index are often preferred, for example, -up to 75 or 100, oreven higher, viscosity index.

In addition to the materials to be added according to the presentinvention, other agents may also be used, such as dyes, pour depressors,heat thickened fatty oils, sulfurized fatty oils, organo metalliccompounds, metallic or other soaps, sludge dispersers, antioxidants,thic'keners,

viscosity index improvers, oiliness agents, resins,

rubber, olefin polymers, voltolized fats, voltolized mineral oils,and/or voltolized waxes and colloidal solids such as graphite or zincoxide, etc. Solvents and assisting agents, such as esters, ketones,alcohols, aldehydes, halogenated or nitrated compounds, and the like,may also be employed.

Assisting agents which are particularly desirable are the higheralcohols having eight or more carbon atoms and preferably 12 to 20carbon atoms. The alcohols may be saturated straight and branched chainaliphatic alcohols such as octyl alcohol, CaHriOH, lauryl alcohol,C12H25OH, cetyl alcohol, CmHsaOH, stearyl alcohol, sometimes referred toas octadecyl alcohol, CmI-Ia'zOH, and the like; the correspondingolefinic alcohols such as oleyl alcohol; cyclic alcohols, such asnaphthenic alcohols; and aryl substituted alkyl alcohols, for instance,phenyl octyl alcohol, or octadecyl benzyl alcohol or mixtures of thesevarious alcohols, which may be pure or substantially pure syntheticalcohols. One may also use mixed naturally occurring alcohols, such asthose found in wool'fat (which is known to contain a substantialpercentage of alcohols having about 16 to 18 carbon atoms) and in spermoil (which contains a high percentage-of cetyl alcohol) and although itis preferable to isolate the alcohols from those materials, for somepurposes, the wool fat, sperm oil or other natural products rich inalcohols may be used per se. Products prepared synthetically by chemicalprocesses may also be used, such as alcohols prepared by the oxidation.of animal or vegetable origin, soaps, and plastics.

Similarly, they may be used in natural and synthetic rubber compoundingboth as vulcanization assistants and as antioxidants, and generally theymay be used in any organic materials subject to deterioration byatmospheric oxygen.

The present invention is not to be considered as limited by any of theexamples described here in which are given by way of illustration only,but it is to be limited solely by the terms-of the appended claims.

We claim:

1. An improved lubricant which comprises an.

oil base and a small quantity, suflicient to sub stantially inhibitdeterioration of the oil during use, of acompound of the formula [(RX)an bPZcLiM in which R is an organic group, X, Y, and Z are elements ofthe group consisting of oxygen, sulfur, selenium, and tellurium, atleast one atom being a member of the class consisting of sulfur,selenium, and tellurium, H is hydrogen, P is phosphorus, M is apolyvalent metal, a, c, and d are small whole numbers, b is zero or one,and a+b+c=3.

2. A lubricant for internal combustion engines which comprises a mineraloil base and a small where R is an oil-solubilizing organic group.

4. A lubricant according to claim 3 in which R in the formula representsan alkyl group having at least five carbon atoms.

5. A lubricant for internal combustion engines which comprises a mineraloil base and about 0.2% to about 5.0% of zinc di(isooctyl phenyl)monothiophosphite.

6. A lubricant for internal combustion engines which'comprises a mineraloil base and about 0.2% to about 5.0% of calcium dioctylmonothiophos'phite.

7. A lubricant for internal combustion engines which comprises a mineraloil base and about 0.2% to about 5.0% of magnesium dioctadecylmonothiophosphite.

JOSEPH F. NELSON. LOUIS A. MIKESKA.

